If Merrick Garland were replacing a moderate like Kennedy, I think he could have gotten that many votes.

There is a reason the GOP wouldn't even put Garland up for a vote - he's a moderate, very well respected judge who is extremely qualified for a seat on SCOTUS. If they put him up for a vote, the GOP would have a hard time voting against him.

I agree. It's a few years outdated, but this article, reporting on a paper published in PLoS One shows that there is ebb and flow to congressional partisanship. The general trend in recent and not-so-recent history has been towards more polarization, but in the third graph you can see some back and forth. Particularly in the late 60's and early 70's, there was more cooperation, being proceeded by a time of less, and followed by increasing polarization until today.

I've love to see this repeated with more historical data. I suspect there was a similar pattern in the lead-up to the collapse of the Federalist party, and in the antebellum years or decades. I'm not saying another civil war is likely, but something where one of the parties (right now, my bet is on the Republicans) fractures or just disintegrates. Whether it's that they nominate someone else, and Trump runs anyway, splitting the moderates and Trumpians, or just with demographic shift over time. The older generations skew Republican, and younger generations do not, so there is not a sufficient "replacement rate" to keep the Republican party relevant (some Pew sources for example: Pew 1 and Pew 2). Unless that trend changes as Millennials age, the Republican party needs to either change its tune, or it will quite literally die off.

It also built up even worse in the mid 19th century, culminating in the civil war. Now I'm not saying this will happen again, I'm saying that don't forget to learn from history. Don't make the mistake of assuming trends will never change, they always do. Either from world events, societal changes, technology, internal political drifting, etc. Things looked pretty damn bad in the 60's with hostile segregation like redlining, riots, and mass violence against civil rights activists and war protesters. But we survived it, and things calmed down.

The political climate has gotten bad before, and it's gotten better before, don't underestimate the human ability to adapt.

Glancing at the history of nominations on Wikipedia it seems possible. These last few have been the most contentious but there have been other times where the margins got thinner in terms of the for and against votes.

Ginsburg might be a modern high water mark of sorts that won't be achieved again but it seems like this narrow nomination voting trend should reverse itself at some point.